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AIM: To investigate the effect of curcumin on oxidized low-density lipoprotein (ox-LDL)-induced injury of human aortic endothelial cells (HAECs).METHODS: HAECs were pre-treated with curcumin at different concentrations and then treated with ox-LDL.The cell viability was assessed by MTT assay.The cell proliferation ability was analyzed by EdU assay.ELISA was used to determine the concentrations of interleukin-6 (IL-6), transforming growth factor β1 (TGFβ1), high mobility group box-1 protein (HMGB1) and secretory receptor for advanced glycation end products (sRAGE) in the HAEC culture medium.The binding activity of peroxisome proliferator-activated receptor γ (PPARγ) was evaluated by electrophoretic mobility shift assay.The protein levels of HO-1, HMGB1, RAGE,IL-6,TGFβ1 and phosphorylated PPARγ in the HAECs were determined by Western blot.RESULTS: The viability and the proliferation ability decreased significantly in the HAECs treated with ox-LDL.The PPARγ/HO-1 signaling pathway was inhibited while its down-stream HMGB1/RAGE signaling pathway was activated by ox-LDL.The levels of IL-6, TGFβ1, HMGB1 and sRAGE were increased.Pre-treatment with curcumin activated PPARγ/HO-1 signaling pathway and inhibited HMGB1/RAGE signaling pathway in ox-LDL treated HAECs in a concentration-dependent manner.The levels of IL-6, TGFβ1, HMGB1 and sRAGE were also decreased dramatically by pre-treatment of curcumin in a concentration-dependent manner.CONCLUSION: ox-LDL induces HAEC damage by inhibiting PPARγ/HO-1 to activate HMGB1/RAGE inflammatory signaling.Curcumin exerts protective effect on ox-LDL treated HAECs via activating PPARγ/HO-1 signaling pathway.
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AIM: To investigate the inhibitory effect of L-carnitine on high glucose-induced apoptosis of human aortic endothelial cells (HAECs) and the molecular mechanisms.METHODS: The apoptosis of HAECs was induced by high-glucose incubation.HAECs were treated with L-carnitine at different concentrations (50, 100 and 200 μmol/L).The cell viability was measured by MTT assay.The cell apoptosis was assessed by Hoechst 33258 staining and flow cytometry.Colorimetric method was employed to detect the caspase-3 activity in the HAECs.The protein expression and phosphorylation levels were determined by Western blot.RESULTS: High-glucose incubation dramatically decreased the cell viability and induced apoptosis.The protein kinase R-like endoplasmic reticulum kinase (PERK), inositol-requiring enzyme-1 (IRE1) and activating transcription factor 6 (ATF6) signaling pathways of endoplasmic reticulum stress were activated to induce cell apoptosis via down-stream caspase-4/3 cascade.However, L-carnitine treatment significantly attenuated the cell apoptosis and increased the cell viability in a concentration-dependent manner.L-carnitine also significantly suppressed endoplasmic reticulum stress and ATF6 signaling in high glucose-incubated HAECs without attenuating PERK and IRE1 signaling.The expression of site-1 protease (S1P) and site-2 protease (S2P) was inhibited by L-carnitine treatment, thus decreasing pro-apoptotic factor ATF6 p50 produced by ATF6 cleavage.CONCLUSION: L-carnitine inhibits high glucose-induced apoptosis of HAECs by inhibiting ATF6 signaling.
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AIM:To study the effects of extracellular potassium on the protein expression of wild-type HERG and its mutant L539fs/47.METHODS:Wild-type HERG (WT) or its mutant HERG-L539fs/47 (MT) were transfected into HEK293 cells for 36 h.The cells were incubated in different media containing 0.8, 4.3 or 10 mmol/L potassium.Af-ter 6 h of incubation, the protein expression of HERG was detected by flow cytometry.After 12 h of incubation, the locali-zation and quantity of the proteins were detected by laser confocal imaging and Western blot.RESULTS: Different from the retention of mutant protein in cytoplasm, wild-type HERG protein was mainly distributed in the cell membrane.The 2 proteins both increased with the changes of extracellular potassium.Flow cytometry showed that the fluorescence in the 2 groups both increased with the changes of extracellular potassium ( P<0.01 ) .The fluorescence in WT group was signifi-cantly higher than that in MT group (P<0.01).Western blot showed that mutant HERG protein included only one 60 kD band, different from the 135 kD and 155 kD bands in wild-type HERG, which were affected by the changes of extracellular potassium (P<0.05).CONCLUSION:The retention of HERG mutant L539fs/47 protein in the cytoplasm is more than wild-type HERG.Chronic high extracellular potassium keeps the stability of wild-type and mutant HERG proteins on the cell membrane.Chronic low potassium reduces the expression of HERG channel proteins in a time-dependent manner.
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<p><b>OBJECTIVE</b>To review the current status and progress on pig islet xenotransplantation.</p><p><b>DATA SOURCES</b>Data used in this review were mainly from English literature of Pubmed database. The search terms were "pig islet" and "xenotransplantation".</p><p><b>STUDY SELECTION</b>The original articles and critical reviews selected were relevant to this review's theme.</p><p><b>RESULTS</b>Pigs are suggested to be an ideal candidate for obtaining available islet cells for transplantation. However, the potential clinical application of pig islet is still facing challenges including inadequate yield of high-quality functional islets and xenorejection of the transplants. The former can be overcome mainly by selection of a suitable pathogen-free source herd and the development of isolation and purification technology. While the feasibility of successful preclinical pig islet xenotranplantation provides insights in the possible mechanisms of xenogeneic immune recognition and rejection to overwhelm the latter. In addition, the achievement of long-term insulin independence in diabetic models by means of distinct islet products and novel immunotherapeutic strategies is promising.</p><p><b>CONCLUSIONS</b>Pig islet xenotransplantation is one of the prospective treatments to bridge the gap between the needs of transplantation in patients with diabetes and available islet cells. Nonetheless, further studies and efforts are needed to translate obtained findings into tangible applications.</p>